What's good for the planet's climate is also good for its food systems.
Halting global warming and feeding the world's rapidly growing population both require major overhauls to the way that humans manage the land they live on, according to a much-anticipated report from the Intergovernmental Panel on Climate Change.
The report, released this morning, tackles the broad connections between climate change and land. With contributions from more than 100 scientists who reviewed thousands of research papers, it dives deeply into the ways that climate change affects the planet's landscapes and how managing those landscapes better can insulate Earth and humans from the risks of rising temperatures.
Climate change and human land-use practices are already contributing to the degradation of landscapes around the world, the authors say. Large swaths of South and East Asia, North Africa, and the Middle East, for instance, have already begun to dry out and transform into deserts. These kinds of changes not only alter natural ecosystems but can pose a major threat to agriculture. That in turn affects the amount of food for humans.
At the same time, the report notes that natural landscapes, including forests and wetlands around the world, are important carbon storage sites. And for the time being, the land still seems to be soaking up more carbon dioxide than it releases.
But deforestation, agriculture, the conversion and development of natural landscapes, and other land-use changes release billions of tons of carbon dioxide and other greenhouse gases into the atmosphere each year. Cutting down on those emissions, while preserving the world's existing carbon sinks, should be a major priority in the fight against climate change, the report says.
These conclusions reflect the findings of other recent studies, which say that "natural" climate solutions — namely, protecting and restoring natural carbon-storing landscapes — can have a profound effect on global climate mitigation.
One study, published in Proceedings of the National Academy of Sciences in 2017, suggested that natural climate solutions could provide up to a third of all the actions needed between now and 2030 to keep global temperatures within 2 degrees Celsius of their preindustrial levels.
"If we continue to degrade ecosystems, if we continue to convert natural ecosystems, if we continue to deforest, if we continue to destroy our soils, we're going to lose this natural subsidy we're getting that's protecting us in part from ourselves, from the damage we're creating as we pump these greenhouse gases into the atmosphere," said Louis Verchot, a scientist with the International Center for Tropical Agriculture and one of the report's authors, at a press conference yesterday afternoon.
Perhaps most notably, the report challenges a long-standing notion that land-based climate solutions are a threat to global food security, competing with agriculture for resources that are needed to feed the expanding population.
Instead, the report points out that climate change is a threat to agriculture and global food security, while unsustainable food systems and agricultural practices can also make climate change worse. The two systems are intrinsically linked. At the same time, sustainable land-use practices can reduce greenhouse gas emissions and increase agricultural productivity. And improvements to the production and distribution of food can also reduce the growing demand for agricultural land, cutting down on the destruction of natural ecosystems.
For instance, the report suggests that improved soil management practices can increase the amount of carbon that soils store — a boon for the climate — while also increasing the productivity of croplands. Cutting down on food waste and food losses further down the supply chain can help improve food security and reduce demand on the production side.
Meanwhile, improved forest management practices — like restoring forests and cracking down on deforestation — can improve carbon storage in places where forests already exist, without requiring additional land resources.
The key is to combine natural climate solutions with other measures to reduce the human demand for land resources, said Pamela McElwee of Rutgers University, another author of the report.
"I would argue that, yes, natural climate solutions are certainly things that we looked at and feel have an important role to play, but when they're combined with demand-side reductions, whether that be dietary change, reducing food loss and waste and so forth," she said. "That's where we get the maximum benefits, and we try to avoid some of those trade-offs with food security."
That's not to say that there aren't any conflicts over land. Some proposed natural climate solutions would, in theory, require large tracts of land. For instance, afforestation — planting new forests in places where they didn't previously exist — could use huge amounts of land.
If these kinds of land-intensive strategies are deployed at large scales, then there would likely be an increasing need for corresponding demand-side measures aimed at reducing agricultural pressure on the land.
In particular, the report is cautious about the potential implications of bioenergy crops grown at large scales.
Some experts have suggested that bioenergy, paired with carbon capture and storage technology, could help draw carbon dioxide out of the atmosphere in a process known as "negative emissions." The idea is that massive plantations of trees and other plants used for bioenergy would take carbon dioxide out of the air as they grow. Then, they'd be harvested and used for energy. Special technology would be used to capture the carbon emissions they produce, rendering the whole process effectively carbon-negative.
But multiple studies have recently suggested that the amount of land, water and other resources required to maintain these plantations — at least, at a scale that would make a substantial difference to the global climate — would likely be unsustainable.
The IPCC report reflects those findings. It suggests that even assuming a future scenario with low population growth, more sustainable land use and lower rates of food waste, any more than a million square kilometers of bioenergy cropland worldwide — that's about 386,000 square miles — could pose a "moderate" risk to food security, land degradation and water scarcity in dry parts of the world.
Still, the report notes that a future without the widespread use of bioenergy will require additional climate action to make up for it.
In these ways, there are trade-offs to be considered. There's only a finite amount of land and other natural resources available on the planet, some of which must be used to feed human populations and some of which must be protected and managed for climate mitigation.
But the report's overarching message is that these two interests have much greater overlap than it may seem at first glance.
"The body of evidence, developed by the global scientific community and assessed by IPCC, points to the potential for strong synergies between climate responses and other goals societies have, including food security and biodiversity preservation," said Katharine Mach, a senior research scientist at Stanford University, who commented on the new report in an email to E&E News.
"As for so much of the climate challenge, the barriers come down to very human factors: can we muster the political will and innovate the institutions needed to scale proven approaches?" she added.
According to the authors, the report is intended only to present the evidence — it's up to policymakers to decide what to do with the information.
"This is basically a road map to help policymakers understand what some of the possibilities are, what some of the potential trade-offs are, how those might be managed," said McElwee. "So it's really up to policymakers to take those findings and then apply them into the situations that fit their particular needs."